[PATCHv2] ARM: drivers/amba: release the resource to allow for deferred probe
diff mbox series

Message ID 20191002123349.23771-1-dinguyen@kernel.org
State New
Headers show
Series
  • [PATCHv2] ARM: drivers/amba: release the resource to allow for deferred probe
Related show

Commit Message

Dinh Nguyen Oct. 2, 2019, 12:33 p.m. UTC
With commit "79bdcb202a35 ARM: 8906/1: drivers/amba: add reset control to
amba bus probe", the amba bus driver needs to be deferred probe because the
reset driver is probed later. However with a deferred probe, the call to
request_resource() in the driver returns -EBUSY. The reason is the driver
has not released the resource from the previous probe attempt.

This patch fixes how we handle the condition of EPROBE_DEFER that is returned
from getting the reset controls. For this condition, the patch will jump
to err_release, which will release the resource.

Fixes: 79bdcb202a35 ("ARM: 8906/1: drivers/amba: add reset control to
amba bus probe")
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
---
v2: release the resource when of_reset_control_array_get_optional_shared()
    returns EPROBE_DEFER
---
 drivers/amba/bus.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Comments

Russell King - ARM Linux admin Oct. 2, 2019, 12:40 p.m. UTC | #1
On Wed, Oct 02, 2019 at 07:33:49AM -0500, Dinh Nguyen wrote:
> With commit "79bdcb202a35 ARM: 8906/1: drivers/amba: add reset control to
> amba bus probe", the amba bus driver needs to be deferred probe because the
> reset driver is probed later. However with a deferred probe, the call to
> request_resource() in the driver returns -EBUSY. The reason is the driver
> has not released the resource from the previous probe attempt.
> 
> This patch fixes how we handle the condition of EPROBE_DEFER that is returned
> from getting the reset controls. For this condition, the patch will jump
> to err_release, which will release the resource.
> 
> Fixes: 79bdcb202a35 ("ARM: 8906/1: drivers/amba: add reset control to
> amba bus probe")
> Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
> ---
> v2: release the resource when of_reset_control_array_get_optional_shared()
>     returns EPROBE_DEFER
> ---
>  drivers/amba/bus.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
> index f39f075abff9..1109437815eb 100644
> --- a/drivers/amba/bus.c
> +++ b/drivers/amba/bus.c
> @@ -409,9 +409,12 @@ static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
>  		 */
>  		rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
>  		if (IS_ERR(rstc)) {
> -			if (PTR_ERR(rstc) != -EPROBE_DEFER)
> +			ret = PTR_ERR(rstc);
> +			if (ret == -EPROBE_DEFER)
> +				goto err_release;
> +			else
>  				dev_err(&dev->dev, "Can't get amba reset!\n");
> -			return PTR_ERR(rstc);
> +			return ret;

Still a negative.

Remember in the comments to the previous patch I talked about ioremap().

Please read the code that you are modifying and carefully consider what
needs to happen at this site to properly clean up on failure.

Patch
diff mbox series

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index f39f075abff9..1109437815eb 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -409,9 +409,12 @@  static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
 		 */
 		rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
 		if (IS_ERR(rstc)) {
-			if (PTR_ERR(rstc) != -EPROBE_DEFER)
+			ret = PTR_ERR(rstc);
+			if (ret == -EPROBE_DEFER)
+				goto err_release;
+			else
 				dev_err(&dev->dev, "Can't get amba reset!\n");
-			return PTR_ERR(rstc);
+			return ret;
 		}
 		reset_control_deassert(rstc);
 		reset_control_put(rstc);